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SI designs rugged, user-focused firearm components and optics. They make accessories like slide plates, charging handles, barrel clamps, red dots, and shotgun parts.
All SI Products (2,383)
Sinclair INTERNATIONAL BRONZE PISTOL BRUSH 44/45 CALIBER 8-32M 12 PACK
Sinclair INTERNATIONAL BRONZE PISTOL BRUSH 10MM/40/41 CALIBER 8-32M 12 PACK
Sinclair INTERNATIONAL BRONZE PISTOL BRUSH 9MM/38/357 CALIBER 8-32M 12 PACK
Sinclair Intl Bronze Pistol Brush 22 Cal 12 Pack
Sinclair INTERNATIONAL BRONZE PISTOL BRUSH 17 CALIBER 8-32M 12 PACK
Sinclair INTERNATIONAL BRONZE RIFLE BORE BRUSH 50 CALIBER 8-32M 12 PACK
Sinclair INTERNATIONAL BRONZE RIFLE BORE BRUSH 41 CALIBER 8-32M 12 PACK
Sinclair INTERNATIONAL BRONZE RIFLE BORE BRUSH 375 CALIBER 8-32M 12 PACK
Sinclair INTERNATIONAL BRONZE RIFLE BORE BRUSH 338 CALIBER 8-32M 12 PACK
SINCLAIR INTERNATIONAL BRONZE RIFLE BORE BRUSH 8MM 8-32M 12 PACK
SINCLAIR INTERNATIONAL BRONZE RIFLE BORE BRUSH 6.5MM 8-32M 12 PACK
Sinclair INTERNATIONAL ROD CASE BRACKET
Sinclair INTERNATIONAL BRN AR-15 SINGLE SHOT FOLLOWER ALUMINUM
Sinclair INTERNATIONAL THOMPSON CENTER ROD GUIDE FOR 35 REMINGTON
Sinclair INTERNATIONAL THOMPSON CENTER ROD GUIDE FOR 6.5X284 WINCHESTER
Sinclair INTERNATIONAL SOLVENT BOTTLES BARRIER TYPE 4OZ 3 PACK
Sinclair INTERNATIONAL ACTION CLEANING TOOL HEAD FOR KIMBER/SMALL SAKO
Sinclair INTERNATIONAL O-RING REPLACEMENT KIT 17 CALIBER 5 PACK
Sinclair INTERNATIONAL ACTION CLEANING TOOL COTTON ROLLS 50 PACK
Sinclair International Scope Ring Lapping Tool Combo Kit
Sinclair INTERNATIONAL TRIMMER CUTTER POWER ADAPTER
Sinclair INTERNATIONAL NECK TURNING HANDLE LARGE 35-50 CALIBER
Sinclair INTERNATIONAL PRIMER POCKET UNIFORMER KIT WITH SCREWDRIVER ADAPTER CARBIDE
Sinclair INTERNATIONAL CASE TRIMMER POWER ADAPTER
Sinclair INTERNATIONAL LARGE CALIBER NECK TURNING MANDREL SS 408 CALIBER (.406")
Sinclair INTERNATIONAL LARGE CALIBER NECK TURNING MANDREL SS 375 CALIBER (.373")
Sinclair INTERNATIONAL LARGE CALIBER STAINLESS EXPANDER MANDREL 408 CALIBER(.407")
Sinclair INTERNATIONAL SOLVENT BOTTLE WITH FLIPTOP LID 4OZ 3 PACK
Sinclair INTERNATIONAL BULLET SORTING STAND WITH DIGITAL INDICATOR
Sinclair INTERNATIONAL BENCHREST HEAVY VARMINT SHOOTING REST LH WINDAGE
Sinclair International Competition Shooting Rest Premium
Sinclair INTERNATIONAL TRIMMER STAND WITH SHARKFIN CLAMP
Sinclair INTERNATIONAL NECK TURNING CASE HOLDER #7 338 LAPUA MAGNUM
Sinclair INTERNATIONAL DIE LOCK RING PLIERS FOR HORNADY & LEE PRECISION
Sinclair International Bullet Comparator 22 Caliber Precision
Sinclair INTERNATIONAL BULLET SEATING DEPTH GUIDE AR-15
Sinclair INTERNATIONAL PILOT STOP STAINLESS STEEL 408 CALIBER
Sinclair INTERNATIONAL PILOT STOP STAINLESS STEEL 422 CALIBER
Sinclair INTERNATIONAL BENCHREST SHOOTING REST WINDAGE TOP RIGHT HAND
Sinclair INTERNATIONAL BENCHREST SHOOTING REST WINDAGE TOP LEFT HAND
Sinclair INTERNATIONAL PREMIUM NECK TURNING TOOL ONLY NT-4000
Sinclair INTERNATIONAL TRIMMER MICROMETER ATTACHMENT
Sinclair INTERNATIONAL SHOOTING REST SPEED SCREW 3/8"X16 THREADS
Sinclair INTERNATIONAL BENCHREST SHOOTING REST NON-WINDAGE REST TOP
Sinclair INTERNATIONAL CARBIDE NECK TURNING MANDREL 6.5MM (.262")
Sinclair INTERNATIONAL CARBIDE NECK TURNING MANDREL 20 CALIBER (.202")
Sinclair INTERNATIONAL CARBIDE NECK TURNING MANDREL 270 CALIBER (.275")
Sinclair INTERNATIONAL CARBIDE NECK TURNING MANDREL 17 CALIBER (.170")
About SI
Headquarters
Established
-
Country of Origin
USA
History & Heritage
SI began as an American aftermarket parts maker aimed at providing functional, affordable upgrades and accessories for shooters. Over time the brand expanded its offerings across pistol, rifle, and shotgun platforms, becoming known for practical designs and broad compatibility.
Notable Products
Popular items include charging handles, slide adapter plates, red dot sights, barrel clamps, and shotgun conversion components.
Why Choose SI?
Choose SI for straightforward, well-engineered accessories that improve usability and durability without unnecessary complexity.
Hot SI Items June 2026
Trending right now based on the last 30 days of TheGunDock orders + page views.
SilencerCo Sparrow 22 Rimfire Suppressor 22LR 5.08" Stainles
SIG SAUER 322C-ROSE-RS P322 Rose 22 LR 4" Black Anodize Semi
Sig Sauer W365XL-9-BXR3P-MS P365 XL 9mm 3.7" Nitron Semi-Aut
Sig Sauer Tango-MRS Compact Rifle Scope 1-6x24 30mm SFP BDC6
Sig Sauer Cross Sawtooth Rifle 6.5 PRC 22 inch Moss Green Fo
Sierra Bullets 4540C 7mm 0.284 Caliber 140 Grain Tipped Boat
SilencerCo AC1278 ASR Black Nitride 9/16"x24 LH Threads 30 C
Sig SAUER Mags 9MM 20Rd Blue P226 MAG-226-9-20
Shop SI Products
Sig SAUER MCX-SPEAR 6.8x51mm SBR 13in Semi-Auto Rifle RSPEAR
SilencerCo Sparrow 22 Rimfire Suppressor 22LR 5.08" Stainles
Sig Sauer P320 FLUX 9MM 3.9" 30RD Legion 320
Sig Sauer SLH300TIQD 300 Blackout Titanium Suppressor
SilencerCo Velos LBP 5.56 NATO/.223 4.76 In Low Back-Pressur
SIG SAUER MCX Spear SBR 7.62x51mm 13" Nitride NFA
Sig Sauer P365X Macro Tacops 9mm 3.7" 17rd Pistol
Sinclair INTERNATIONAL DIAL INDICATOR .001
Sig Sauer ROMEO1 Black Shroud Kit SOR1SK001: Medium Size, Ne
Sig Sauer 8900823 LTXG Grip Module Laser Engraved P320-X Car
Sig Sauer MCX-SPEAR LT AR Conversion Kit 5.56 NATO 11.5" Bla
Sig SAUER MCX 5.56 NATO 16in 30rd IR Cerakote FDE Rifle RMCX
SI News & Articles
Firearm Shipping Restrictions by State (2026 Update)
State-by-state guide to firearm and ammunition shipping for online buyers and FFL dealers. Current as of May 2026. Cover...
Damaged in Transit: How TheGunDock Handles Shipping Claims on Firearms and Ammo
When a firearm or ammo shipment arrives damaged, the claim process matters. TheGunDock walks through what to do, what we...
The Springfield KUNA: Roller-Delayed 9mm Pistol That's Shaking Up the PDW Market
The Springfield Armory KUNA — a roller-delayed 9mm pistol built in partnership with Croatia's HS Produkt — has becom...
The Strait of Hormuz: 2,500 Years of Trade, Arms, and Conflict
A twenty-one-mile-wide choke point has shaped the movement of goods — and weapons — across half the ancient and mode...
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Choose SI for straightforward, well-engineered accessories that improve usability and durability without unnecessary complexity....
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